I see. I understand now. It would indeed be quite the load if you were to change it all of a sudden. Apologies for not taking that into account!
Still, 900 seconds is really long, especially for a single H event. I simply hope that you can think of a way to solve this problem, since seeing other comments here, it seems to be an issue worth checking out.
Food for thought, adding an option for the JOI mode or a short version right before the feeding session (like the mood selection) could be interesting. Of course, the decision is up to you.
Regardless, I'm wishing you and this game the best of luck! I'll be sure to check out this page occasionally.